RDWorks Learning Lab 222 Beam combiners A new approach

I looked at the performance of beam combiners more than 4 years ago and decided then that it was impossible to set them with any precision. I have managed for 6 years without one and at the last review, I power tested before and after to find a 5% power loss. I thought this was a heavy premium to pay for an unpredictable indication of where the beam would hit your work. Cloudray are most insistent that a beam combiner is the only way to provide a "red dot" for the lightweight head on the Russ Spec machine they have produced. I found myself with a dilemma......... agree to shipping a high spec high quality machine with a piece of known substandard kit or design a replacement that would do the job properly. I accepted the latter challenge and this video is an an analysis of the task to be performed and then testing the design that I created.

[@ChristofVorhauer]

Amazing like always, Russ, from impossible to the perfect solution in a 'minute'

[@ralphzito7609]

That’s awesome Rus , master class in beam alignment, now I’ve got another project! Thanks Mate! Best regards Ralph

[@juddstapleton6285]

I look forward to Cloudray coming out with your beam combiner that actually works and can be adjusted from the correct side. Thanks Russ

[@terryevans1976]

Absolutely excellent video Russ. Hopefully Cloudray will be interested in building these beam combiners for those of us who want to add them to our current machines.

[@SarbarMultimedia]

Hi Terry Thanks for the kind words. I think it will be part of the production Russ spec machine. As a spare part? I have suggested they adapt the design for general use but an inquiry may prompt them and make them realise there are potential sales waiting. Best wishes Russ

[@terryevans1976]

@@SarbarMultimedia Thanks Russ, I'll contact Cloudray.

[@polakis1975]

Genius as always mate!

[@nraynaud]

re-watching that video one year later. I think we can to an incremental improvement. Combine the first mirror, the beam combiner and the red laser on the same plate. Affix the red laser next to the mirror, pointed towards the laser tube (IE backwards), and the combiner between the CO tube and the first mirror (of course). That way the red laser does almost a 180° refection on the combiner, the CO laser has an almost straight shot to the mirror, so you get very little deflection with the refraction in the combiner, your combiner is presenting a very broad target to the CO2 laser. I don't know if I'm missing something, it's just an intellectual experiment.

[@anthonymyers-35]

My friend I must say thank you for all your trial and error! I'm currently going through the same process and it's driving me nuts. You would think it would be much easier!!!!!! So many little adjustments here and there.

[@jeanbarbier9448]

Dear Russ, Very interesting follow-up of your previous video... I like a lot the way you don't take anything for granted and verify any 'obvious' principle on the real field. I still believe that 'my' idea of a pointer on a tray past the 1st mirror (or according to you Peter Jensen' one) can be valid with the the caveat of having all the 4 needed degrees of freedom that you have experimented, but probably with a much less convenient decoupling of adjustments... Thanks again for your patience...

[@SarbarMultimedia]

Hi Jean Provided your design allows you to set the red dot to meet the parallelism and offset requirements then it will work on a withdrawal system. I haver to say that playing with my system for just a few hours annoys me to see the red dot at the cut point contiuously. Many people love it so I cannot foist my personal taste onto others. Cloudray believes it is an important marketing feature so I have to go along with it now that it works. Best wishes Russ

[@bobuilt10]

@@SarbarMultimedia My daughter loves the red beam, I'm not so keen so simply put it on a toggle switch.I think it's a confidence thing, she likes to make sure she has her origins correct by framing the job every time. I'm a little more gung-ho. A Great incite once again in to how to align. I have to admit that using a well calibrated red dot will simplify mirror and tube alignment so I will be taking your lead once Xmas is out of the way. Thanks once again Rus.

[@TheLumberJacked]

He explains it so well that he makes me feel smart, but in reality, I feel like a dumb dumb the whole time 😂

[@ShopperPlug]

Excellent explanation. Laser optic meteorology, good stuff. Where did you learn all of this alignment and 10:1 ratio laser beam approach? I would see these results but would hate to assume ratios, your explanation makes more sense and logical. Would be nice if you gave us the build CAD files for it.

[@domingomolinero9553]

Thanks Russ, another very informative video. Have you measured the power loss in the beam combiner?

[@SarbarMultimedia]

Hi Domingo When I first looked at this problem 4 years ago I did measure power loss at about 5% but I have not yet tested this one. I will wait for the Cloudray prototype before I carry out that test. This was just my working modle to prove I was not deluding myself. Best wishes Russ

[@J042578c]

This is a great video and a wonderful design! Please post an update on where I can buy one, if you decide to sell them. I would love to install one on my machine.

[@SarbarMultimedia]

Hi Jeremiah I have no plans to build and sell them myself but I think they will be standard figment on the new Russ spec machine Cloudray will soon start selling. I have suggested to Cloudray that they modify the design to make it more universal for others to buy separately. Yours is not the first inquiry so I suggest sending a note to Cloudray to see if/when they plan to sell such a device. Many thanks for your interest.Best wishes Russ

[@cncdavenz]

I can see now why scientists working with laser beams always use a granite surface. Thanks for the video i will now be keeping my beam combiner and cutting a hole in the side of my machine.

[@SarbarMultimedia]

Hi Dave Cutting a hole in the side of your machine is of little value unless you have the adjustments on your beam combiner to do the X and Y offsets. Also, as I demonstrated, you can set the combiner after mirror 1 without cutting that hole. Best wishes Russ

[@jackroberts8432]

@@SarbarMultimedia I'm slightly confused on how you set the red dot after mirror one. Did you simply adjust mirror one to point away from mirror 2 and send both beams a distance away onto a wall out the front of the machine? You talked about aiming at the corner of mirror 2 frame.... that's all I have seen. Thanks though, I think that will work but just wanted to clarify.

[@Luis__Martin.]

Hello, I use the other Cloudray combiner installed between the first and second mirror, just in front of the second mirror and it works perfectly.

[@SarbarMultimedia]

Hi Luis. The closer you get to the lens the less the errors you will see. Its a good idea that you have mounted it after mirror 1 and I am sure you are happy with the setting you achieved. However, the standard red dot that you see on the workpiece is not a pin prick of light but usually has a dimension that will be between 2 and 3mm diameter. To satisfy yourself that it is perfectt at all table corners can I ask you to measure your red dot diameter aprox (say 2mm) and draw 4 little targets 2mm diameter with a cross hair.Place the targets at each corner of the machine and set the red dot perfectly into the target circle. A quick pulse to burn a dot will indicate how perfect your settings are. Even with a small red dot, my pulse dots were not perfect, just quite good at +/- 0.2mm at 4 corners and the table centre. This is not criticism of your "perfect" or a competition but I would genuinely be really interested in the data if you can provide it. Best wishes Russ

[@Luis__Martin.]

​@@SarbarMultimedia Hello, I made the measurements and in the two on the right side, I have 0.5/0.6mm points. on the left side almost 1mm. Also point out that I have regulated the laser pointer so that it gives a point that is as small or compressed as I could, since without regulating it a line would come out, not a point. All the best.

[@SarbarMultimedia]

@@Luis__Martin. Hi Luis Sincere thanks for carrying out this test. It does demonstrate that perfection is a relative term. In my case I made things better by creating a smaller spot with the red pointer. This is a laser pointer and as with all lasers, the center of the beamis significantly more intense than the edges. If you go back into the video you will see that I made a small masking aperture to limit the light coming from the red laser. I used only the most intense cental part of the beam. For approximate location of material 1mm or better is good enough for most applications. To be honest I never have the need for it so mine is peremenantly swithed off (it runs off a battery pack) If I need to really accurately align material I just do a pulse. I have never used it after making this video. Best wishes and thanks again Russ

[@jackroberts8432]

@SarbarMultimedia I'm slightly confused on how you set the red dot after mirror one. Did you simply adjust mirror one to point away from mirror 2 and send both beams a distance away onto a wall out the front of the machine? You talked about aiming at the corner of mirror 2 frame.... that's all I have seen. Thanks though, I think that will work but just wanted to clarify. Edit... I guess you aimed at the edge of mirror 2 frame while at back and then when moving to front it misses the frame and goes to the wall.... took a moment but I think that's what is done... correct?

[@SarbarMultimedia]

Spot on Jack.. Most people will not want to remove a mirror to fire out the end of the machine. I did thid to illustrate the simple principle of beam alignment. It is not a one adjustment process. To set the red dot PARALLEL to the laser beam will take 4 or 5 adjustments because using a close and then distant target is an iterative process Each time you go through the ANGULAR adjustment process you get closer to perfect parallelism. That's about all you can do with all existing beam combiner systems and that will not work properly. There is a vital final set of horizontal and vertical adjustments that are required to put your now-parallel beam COINCIDENT with the axis of the laser beam. . The second method as you have now worked out is a less disruptive way to carry out the same alignment process.. Good luck Russ

[@jackroberts8432]

@@SarbarMultimedia Thanks Russ, makes perfect sense. I have had my laser for a few years (50W China blue like yours that was spot on out of the box and has worked well so far)and just replaced mirrors so I had to do the alignment for my first time. Went pretty well.... easy really after my indulgence of video input. :-) Thinking about a combiner and thus the interest. Tip of the day - When you are using the card targets, Use 3 to start with and you will protect your mirrors. I have a 25mm (? would have to double check the size but its the size of the hole in the window) circle drawn with cross hairs and this is drawn on a rectangular card that is sized to the window frame for easy and accurate placement. I never dirty a mirror like this as I try not to burn through, only mark enough to see. Small piece of tape on top and bottom of the rectangle secures it to the window frame. When the target is too busy I just tape a new one right on top till I get that mirror done.

[@ryszardx4296]

Will you be supplying a parts list for the combiner in the near future?

[@SarbarMultimedia]

I retired form manufacturing several years ago and enjoy delving deep into the non-metal cutting technology as a retirement pleasure. Unfortunately I keep coming across things that need improving and so the design engineer in me keeps resurfacing. Creating a video diary of my learning journey is also provides lots of material for my other hobby,video editing. In turn this exposes me to requests such as yours. There are several products that I do still manufacture myself but I have formed a very trusting and informal relationship with Cloudray whereby I give them my designs to manufacture so that they will always be available for the laser community long after I am fixing St Peters big laser machine!!! As the video shows this is currently a simple model I cobbled together from materials and parts I had to hand. The design has now been taken up by Cloudray and I will soon be testing their proper production prototype. Although this design is specifically for the Russ Spec machine, I have suggested to Cloudray that they may wish to integrate the principles into a more universal product that you will be able to buy seperately. Best wishes Russ

[@konstantinNeo]

About combining 2 co2 laser sourcer from tubes, can it be done? I vaguely understand something about polarization and the need to have both tubes to be correctly polarized for beam combining to happen but I dont know all the details. Have you experimented with combining two co2 laser sources from tubes?

[@SarbarMultimedia]

Hi My goal is to understand how laser technology works for these Chinese machines and if possible make improvements as I learn. What you are imagining is probably not around for a simple reason of physics. Laser light has one special property, Coherence. That means that all the light waves in a beam are the same length and fully phase synchronized ie they act as one big wave but at trillions of cycled per second. There is a principle of wave theory called constructive and destructive interference. That means that the light waves from BOTH laser beams would have to be completly IN-PHASE, and travelling in the same direction or there would be degrees of destructive interference that could result in ZERO power output. I am not a physicist so dont take my word for it , do a bit more research for yourself on this subject Best wishes Russ

[@MacroLab3D]

Longer testing distance will increase the accuracy.

[@SarbarMultimedia]

Perhaps my communications (diagrams) were unclear . Longer testing distances will make the beams more parallel. More parallel does not improve the axial coincidence. Study the two crosshairs diagram and the effects of parallel and non parallel beams passing through a lens. and I hope you will then understand the concept. Thanks for your comment . My answer is no criticism of yourself because it appears that most others (including designers) have the same quick mental visualization of the problem. Thus your comment may allow others to stop and think.

[@MacroLab3D]

@@SarbarMultimedia You are right! Thanks for clarifying!

[@SarbarMultimedia]

@@MacroLab3D Excellent, not that i'm right, but that you have understood. Even I didn't fully understand until I sat down and worked through it logically . Thanks for the reply.

[@c3tech920]

I bought the beam combiner from cloudray, do you know the voltage for the red laser bean the supply?

[@SarbarMultimedia]

Generally they are 5vdc but look on the silver foil label, it always specifies the voltage there..

[@c3tech920]

@@SarbarMultimedia The laser pointer just came wrapped up in a coil in a zip lock bag with the other products and no instructions. But im pretty sure you are right with it being 5v. Thank you!

[@SarbarMultimedia]

​@@c3tech920 If you go to the web page for the combiner and scroll down, you will findan "ask a question" section.. Worth checking to be sure

[@sparrow082]

Wanna see something interesting? Absolutely recommend wearing proper laser glasses while doing this. Put a lens in a tube and set it to the proper focal height over a piece of scrap wood, but do not install the nozzle. Make sure you use air or off to the side.

[@SarbarMultimedia]

Hi Adam Like this you mean? see kzbin.info/www/bejne/bWq5i52Dmct1o6s at 16:59 for a minute or so. Is this what you expected? Best wishes Russ

[@sparrow082]

@@SarbarMultimedia No not quite. Similar setup though. Put a lens and a lens tube and set the lens to its appropriate focal height above a piece of scrap wood, just don't install the nozzle and hold down pulse for a few seconds over your scrap wood.

[@SarbarMultimedia]

@@sparrow082 Hi Adam . I'm intrigued. Did you move on through the video a bit because I do cutting with this zero airflow setup exactly as you are suggesting. The nozzle I'm using is of no consequence because it has a massive 6mm hole in the end and may as well not be there. So I seem to have simulated your specified conditions.. Will I see something new? Best wishes Russ

[@sparrow082]

@@SarbarMultimedia You will need appropriate air flow you will just have to hold it in your hand off to the side. I don't want to give away the goose but something will occur outside of the cutting area a few seconds after you begin the cut.

[@SarbarMultimedia]

@@sparrow082 Hi Adam It will be a day or two before I can put in some machine time, so I am not ignoring you Russ